Occupied East Jerusalem – In early November, the Israeli authorities summoned Hashim Matar* to the police station in occupied East Jerusalem.

For 10 days, he was interrogated about whether he supported Hamas and was a member of the Palestinian group. Between questioning, Matar was locked in a small room with other detainees, where they were punched, kicked and beaten with batons.

“Lots of people had their [sternum] or heads broken, often gushing with blood,” Matar, a 54-year-old man with a short grey beard and laugh lines around his eyes, told Al Jazeera three months after he was released from detention.

“We weren’t even treated like animals. At least animals are treated with some sort of dignity.”

Israel has taken thousands of Palestinians captive since Hamas’s attack on Israel on October 7, in which 1,139 people were killed and about 250 abducted.

Since then, the number of Palestinians arrested in the occupied West Bank exceeds 7,350 people, according to the Addameer monitor in Ramallah.

While some Palestinians have been released, 9,100 remain captive. That’s a sharp uptick from the 5,200 that were in Israeli prisons before October 7.

These figures do not include the thousands of adults and children the Israeli army has reportedly detained, tortured and interrogated in makeshift prisons across Gaza, outside any legal or civilian oversight.

Violence and neglect

Since October 7, Israeli authorities have become more violent during arrests, according to a staff member of Addameer who spoke on condition of anonymity.

The individual told Al Jazeera that Israeli authorities often storm homes in the West Bank and begin to kick, punch and beat everyone inside. In some cases, Israeli soldiers take family members “hostage” by threatening to whisk them away, unless the wanted person comes forward.

Once in custody, Palestinians are shoved into vehicles and beaten until they arrive at the detention facility. That is where they are told to strip, get dressed and to strip again – a cycle that occurs several times while they are beaten, sometimes on their genitalia.

Captives are subjected to even worse treatment behind bars. Addameer said water or electricity is cut off and captives are denied visits from their relatives or the Red Cross. The rights group added that most victims are denied healthcare, even for injuries sustained during their arrest. As a result, prisoners have died due to health neglect.

“So far, 10 prisoners from the West Bank [have died]. This is the highest figure ever in such a short period,” the Addameer staff member told Al Jazeera.

Matar was afraid he might fall ill during his time in prison. He described how Israeli guards would turn the lights off during the day so captives languished in the dark and flood the cells with light at night to keep prisoners awake as they lay on the cold floors.

However, being beaten was the worst part of detention, Matar said.

“I would ask them: ‘Why are you beating us? What did we do to you for you to beat us?’”

Administrative detention

Israel has also weaponised quasi-judicial measures to arrest thousands of Palestinians without charge. Of all Palestinians detained since October 7, about 3,050 are held in “administrative detention”, an emergency measure that Israel inherited from the colonial British Mandate for Palestine. 

Under administrative detention, prisoners are held indefinitely and given no information about the charges against them or the ostensible evidence incriminating them.

In many cases, Israeli authorities do not inform Palestinian families of the whereabouts of their detained loved ones – which amounts to an enforced disappearance, a violation of international law.

“Israel’s sweeping use of administrative detention is not lawful,” said Omar Shakir, the Israel-Palestine director at Human Rights Watch.

“But these practices don’t just date back years, but decades and they have only escalated since October 7.”

The Addameer staff member added that among 200 Palestinian children languishing in Israeli prisons, 40 are held under administrative detention, and captives suffering from severe or terminal illnesses are denied seeing family and have little hope of being released.

At the end of February, the Addameer staffer said, one cancer patient died in an Israeli prison at the age of 23.

“He just collapsed. He died after five months of not being able to see his family,” they told Al Jazeera.

“This is cruel collective punishment. Just imagine [this person’s family] who lost their beloved. They weren’t even able to be with him in his last moments.”

Makeshift prisons

In addition to the sweeping arrests in the West Bank, the Israeli army has arrested thousands of Palestinians from Gaza since launching its devastating war on the enclave.

Over the last five months, Israel has killed more than 31,000 Palestinians and displaced nearly the entire population of 2.3 million people in Gaza. Many have also gone missing, raising fears that they are either buried under the rubble or languishing in the labyrinth of makeshift Israeli prisons in Gaza.

Ibrahim Yacoub*, 29, was arrested by Israeli soldiers in northern Gaza on November 21. He said his hands were tied behind his back and he was forced to walk to an Israeli detention spot in a group of 80 captives.

“Any time one of us stumbled, a soldier would hit us on top of the head,” he told Al Jazeera. “I kept dreading when they were going to hit me next.”

Yacoub was eventually taken to what appeared to be an empty warehouse, where Israeli soldiers interrogated him, repeatedly asking about Hamas’s operations and his role in the group.

“I kept telling them that I’m not a fighter. I’m a civilian,” Yacoub said over the phone, weeks after his release.

During his 53 days in captivity, Yacoub was moved to two other locations, where he was mistreated, bitten by attack dogs and practically starved. However, he was not among the 1,073 Palestinians transferred to Israel from Gaza, as documented by Addameer.

Despite being released, Yacoub is not free.

He is now in Rafah, a small town by the Egyptian border that is harbouring more than a million Palestinians displaced within Gaza. For weeks, Israel has threatened to launch a full-scale offensive on the town, a move that would compound Gaza’s devastating humanitarian crisis.

Like so many Palestinians, Yacoub doesn’t have the means or freedom to flee. But neither can he imagine building a new life in Gaza from scratch.

“Everything I knew is gone … my apartment and my office,” he told Al Jazeera. “My entire life and future is up in flames.”

* Names have been changed or withheld to protect sources from reprisal.